why remove query param named 'language' in org.restlet.engine.application.TunnelFilter#processQuery

[standzhou2]

we defined a resource using restlet (version: 2.4.3), which could query by GET /rest/regions?param1=xx&language=zh_CN
but in server side, we could not get query param language by getRequest().getResourceRef().getQueryAsForm().getFirstValue

debug step by step, we find in org.restlet.engine.application.TunnelFilter#processQuery, restlet framework remove query param named language

why remove these query params below, our business want to use this named query param!